As depicted in FIG. 1, a control system 100 comprises: a controller 110 for receiving an input signal IN and an output signal OUT and for generating a control signal CON in accordance with a difference between IN and OUT, and a controlled apparatus 120 for generating the output signal OUT in accordance with the control signal CON. The controller 110 adjusts the control signal CON in a closed-loop manner so as to make the output signal OUT tracks the input signal IN. The purpose of the control system 100 is to control the controlled apparatus 120 so that the output signal OUT tracks the input signal IN. A typical controller comprises: an error detector for generating an error signal representing a difference between the input signal IN and the output signal OUT, and a filter for filtering the error signal into the control signal CON. In a practical embodiment, the control signal CON usually contains a noise component. If, due to constraints in practical embodiments, the controlled apparatus 120 is very sensitive to the control signal CON, the output signal OUT may be very noisy because it may overreact to the noise component.
What is needed is a method and apparatus for reducing sensitivity to noise for a control system that comprises a very sensitive controlled apparatus.